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Shuttle is on - maybe

The launch is planned today despite a debate about safety, but storm clouds could cause a delay.

By CURTIS KRUEGER
Published July 1, 2006

CAPE CANAVERAL - NASA administrator Michael Griffin gave a typically blunt answer when asked if he was "playing the odds" by deciding to launch the space shuttle Discovery today.

"You're not going to like this, and I'm sure I'm not going to like how it sounds in print, but we are playing the odds," Griffin told reporters Friday. "What you pay us for as taxpayers is to understand those odds in great detail."

Griffin has taken heat in recent weeks for deciding to go ahead with the launch of Discovery, even though the agency's safety chief and chief engineer recommended against it.

It's part of a larger debate about how much risk is acceptable. And because NASA is actively designing rockets that one day could take astronauts on a three-year mission to Mars, it's a debate that won't disappear soon.

"We live in a time when we're trying to learn how to do space flight, not in a time when we know how to do space flight," Griffin said. "These are learning steps that we're taking, as humbling as that may be to observe."

As the debate continues, Discovery is waiting on the launch pad. Officials hope to fill its giant external tank with super-cold liquid hydrogen and oxygen fuel today and launch at 3:48 p.m. But because of the possibility of storm clouds, forecasters said there was only a 40 percent chance that the launch would go off, and the forecast is no better Sunday and Monday.

The two officials who objected to Discovery's launch have said they worried that foam could fall off the shuttle's external tank, the giant orange torpedo-shaped container that supplies the spacecraft with rocket fuel during launch.

The two said they didn't think the potential problem would endanger the crew, but falling foam is nonetheless an extremely sensitive issue for NASA because that's what damaged the shuttle Columbia on its 2003 launch and cost the lives of its seven astronauts when the shuttle burned up on re-entry.

A NASA official said in an internal e-mail that Griffin was "rolling the dice" by going ahead with the launch, the Orlando Sentinel reported.

All this has led critics to suggest NASA may be repeating mistakes that led to the loss of two previous shuttles. They say the agency has a slavish devotion to launch schedules and has a blind spot when it comes to some of the risks of human space flight.

Griffin denies it. He said he has spent weeks poring over scientific data to learn more about the potential dangers of the falling foam in the current design of the tank. He said he is studying the dangers, not avoiding them.

He acknowledged that NASA failed to recognize the danger of the foam; a mere 1.6-pound chunk of it knocked a hole in Columbia's left wing, allowing superheated air to act like a blowtorch as the ship prepared to land.

Griffin said that NASA intends to fly space shuttles on 16 missions by September 2010 to finish the international space station and that waiting until the external tank is redesigned would create more time pressure at the end of the schedule.

If there is a foam problem on this flight, NASA officials think it will be in an area called ice frost ramps. NASA associate administrator Bill Gerstenmaier said several cameras will be aimed at that area during launch. Launching today, he said would improve safety in the long run by providing information that will help engineers redesign the tank.

The foam is designed to insulate the external tank and keep the fuel inside it at optimum temperature - minus 297 degrees for the liquid oxygen and minus 423 degrees for liquid hydrogen.

Griffin said there are many other risks to the space shuttle besides foam, such as the one-in-a-"couple-hundred-or-so" chance that the spacecraft could be hit by a small meteorite, something that could cause devastating damage.